February 25, 191 5] 



NATURE 



697 



equal ; often strikingly acute it is often as notably 

 weak, e.g., his identification of life and mind. 

 Convincing as a refutation of crude materialism, 

 the book is scarcely so in its more ambitious aims. 

 (3) Swedenborg's "Principia" suggests again 

 the distinction between the examiner and dis- 

 coverer points of view. As a candidate Sweden- 

 borg would deserve high marks; "nothing can 

 dim the glory of this magnificent dash into the un- 

 known," and it is easy to recognise in him anti- 

 cipations of modern physical theories. But, alas ! 

 we want views which will not merely be consistent 

 with future results, but will bring these nearer. 

 There remains, no doubt, the purely historical 

 interest, but the history of ideas is peculiar inas- 

 much as what was helpful in the past is preserved 

 in the present, while the errors, though inevitable 

 at the time, were not merely unsatisfactory as 

 "models," but as mental habits had to be pain- 

 fully unlearnt. Hence to the student of a science 

 its history is apt to be confusing rather than help- 

 ful; and this difficulty one cannot but feel in the 

 case of (4) Prof. Dessoir's history, even though the 

 history of psychology is itself psychology, and 

 excellently as the task is done. The translation 

 reads well, but surely " moment " in the sense of 

 "factor "is still somewhat German English? 



C. S. 



OUR BOOKSHELF. 



Artificial Waterways of the World. By A. B. 

 Hepburn. Pp. xi + 171. (New York: The 

 Macmillan Co.; London: Macmillan and Co., 

 Ltd., 1914.) Price 55. bd. net. 



This book, dealing principally with American 

 waterways, also contains a short account of the 

 principal canals of the world, and is well worth 

 the attention of those interested in internal 

 navigation. 



The object of the author is stated to be to place 

 before the public the salient facts as to internal 

 artificial navigation in relation to commercial 

 development. The author considers that the use 

 of canals is to supplement and complement, and 

 not to attempt to rival railways. 



Canals have not now the same importance in 

 the transport of materials and the development 

 of the resources of England that they have in 

 America, with its enormous area of inland 

 country situated a long distance from the sea- 

 coast. In Great Britain there are no fewer than 

 eight first-class ports situated within compara- 

 tively short distances from the interior, and there 

 is no large manufacturing town more than eighty 

 miles from the sea-coast. 



An interesting account is given of the original 

 construction and subsequent improvements of the 

 Erie Canal, the principal artificial waterway in 

 the United States. This canal connects the 

 country around Lake Erie with the seaport at 



Xew York. It was opened for traffic in 1825, 

 and has, from time to time, been enlarged and 

 improved, and is now capable of taking barges 

 150 ft. long and carrying 240 tons. It is State 

 owned and now toll free. For a quarter of a 

 century it was the greatest transportation line in 

 the country, giving settlers in the west country 

 an outlet for their products. With its con- 

 nections it is 433 miles in length, and second only 

 to the Great Canal of China among the artificial 

 waterways of the world. Its importance has, 

 however, been considerably diminished, the ton- 

 nage carried by this canal being now only about 

 one-twentieth of that carried by the railways. 



The British Journal Photographic Almanac, 1915. 

 Edited by G. E. Brown. Pp. 1068. (London : 

 Henry Greenwood and Co., Ltd.) Paper, is. 

 net; cloth, 25. net. 



This volume is the fifty-fourth issue of the photo- 

 grapher's most useful companion, and will be 

 found to be up to the usual standard of accuracy 

 and completeness. 



Two notable articles of great interest to amateur 

 workers are those of " Modern Methods of En- 

 larging," by the editor, and "Photograph}' with 

 the Microscof)e," by Dr. Duncan J. Reid. Both 

 of these deal with the subjects in clear and pre- 

 cise style, and are well illustrated by carefully 

 selected diagrams. The resume of the year's 

 practical work and the section on novelties 

 in apparatus bring the reader right up to 

 date as regards methods and apparatus. The 

 volume embodies as usual the many formulae and 

 tables needed in the practical man's work and 

 such useful information as particulars of the 

 photographic societies in the British Empire, etc. 

 Bv no means unimportant is the well-arranged' 

 mass of advertisements of the numerous photo- 

 graphic firms in which the announcements of 

 apparatus and materials are of great interest to 

 the practical worker. Complete indices to text 

 and goods advertised make the mass of valuable 

 information included in these 1068 pages readily 

 available. 



Heaton's Annual. The Commercial Handbook of 

 Canada and Boards of Trade Register, 1915. 

 Edited by E. Heaton and J. B. Robinson. Pp. 

 516. (Toronto: Heaton's Agency; London: 

 Simpkin, Marshall, Hamilton, Kent and Co., 

 Ltd.) Price 55. 

 The eleventh annual issue of this useful work of 

 reference will be welcomed by all who have com- 

 mercial or other dealings with Canada. The de- 

 tailed information is brought together in a form 

 which makes it easily available, and it will prove 

 of assistance to teachers of commercial geography 

 as well as business men. This year, for the first 

 time, an economic bibliography of the Dominion 

 and Provincial Government reports has been 

 added. The general information includes valuable . 

 notes on agriculture, technical education, fisheries, 

 mining, and temperature and rainfall among other 

 matters likely to appeal to students of science. 



